Adjustable lumbar supports are provided in motor vehicles to provide for differing driver requirements and to increase driver or passenger comfort. Many adjustable lumbar supports are known and described in U.S. Pat. Nos. 3,948,558, 3,973,797, 4,462,635, 4,531,779, 4,534,592, 4,564,235, 4,630,865, 4,632,454 and 4,714,291 and in Australian patent or patent application Nos. 72822/81, 80449/82, 19524/83, 47090/85 (575427), 63973/86 and 72609/87.
One particular known support is described in Australian lapsed application No. 80449/82. The support comprises a "waist band" extending between two brackets fixed within and on either side of the frame of a vehicle seat. On one side of the seat frame, the waist band is pivotally attached to the bracket in a fixed position by way of a pivot pin. The pivot pin, which generally includes a nylon or other bush is fixed in pivotal arrangement by an appropriately formed plate which encircles the pivot pin and bush and terminates in two parallel spaced apart plates. The waist band is inserted between the plates and fixed by appropriate means such as riveting.
On the other side of the seat frame the waist band is again pivotally attached to a bracket in a manner similar to that described above. The bracket however includes adjustment means to reduce or increase the distance between the ends of the waist band to enable the required adjustable lumbar support. The adjustment is provided by forming the bracket in two parts which are hinged or pivotally fixed on the moveable part which acts as a cam follower. A cam which may be a continuous or stepped cam is operated by an appropriate handle attached to a spindle to permit the desired adjustment.
The known prior art lumbar supports are complicated and thus relatively expensive to manufacture. A lumbar support as is described in the above mentioned patent application requires many parts including the fixed bracket, pivot pin and bush, the waist band plate, the waist band, a further waist band place and associated pivot and bush, a two part bracket pivotably connected to permit appropriate adjustment all in addition to the cam, the cam drive spindle and handle.
In lumbar support devices as have been described above, the waist band may be a belt or belt like band of any suitable material. It is customary that waist bands are made of a stiff but flexible material such as a sheet of nylon, polypropylene polyethylene or the like. It is also customary that a pad of resilient foam is attached to one side of the waist band to provide additional cushioning to the lumbar region of the seat when fitted with such a device and waist band.